CI: switch workflow to x86_64-linux to prevent rate limiting Signed-off-by: Leo Moser <leomoser99@gmail.com>

diff --git a/.github/actions/setup_nix/action.yml b/.github/actions/setup_nix/action.yml
new file mode 100644
index 0000000..59ef361
--- /dev/null
+++ b/.github/actions/setup_nix/action.yml

@@ -0,0 +1,46 @@
+name: Install Nix
+description: Installs Nix or a Nix-compatible flake fork, while also enabling
+  the requisite caches.
+inputs:
+  shell:
+    description: "Shell to use for glue logic"
+    required: true
+    default: "bash"
+  github_token:
+    description: "A token for the Nix daemon to use when fetching information from GitHub"
+    required: false
+    default: ""
+  nix_cache_domain:
+    description: "An additional https-hosted Nix build cache"
+    required: false
+    default: ""
+  nix_public_key:
+    description: "The public key for the aforementioned Nix cache if specified"
+    required: false
+    default: ""
+runs:
+  using: "composite"
+  steps:
+    - name: Set GitHub Token Config String
+      if: inputs.github_token != ''
+      shell: ${{ inputs.shell }}
+      run: |
+        echo "GITHUB_ACCESS_TOKEN_STR=${{ inputs.github_token }}" >> $GITHUB_ENV
+    - name: Set Nix Cache Config Strings
+      if: inputs.nix_cache_domain != '' && inputs.nix_public_key != ''
+      shell: ${{ inputs.shell }}
+      run: |
+        echo "EXTRA_SUBSTITUTER_STR=https://${{ inputs.nix_cache_domain }}" >> $GITHUB_ENV
+        echo "EXTRA_TRUSTED_KEY_STR=${{ inputs.nix_public_key }}" >> $GITHUB_ENV
+    - uses: DeterminateSystems/nix-installer-action@main
+      with:
+        determinate: false
+        extra-conf: |
+          access-tokens = ${{ env.GITHUB_ACCESS_TOKEN_STR }}
+          extra-substituters = ${{ env.EXTRA_SUBSTITUTER_STR }} https://nix-cache.fossi-foundation.org
+          extra-trusted-public-keys = ${{ env.EXTRA_TRUSTED_KEY_STR }} nix-cache.fossi-foundation.org:3+K59iFwXqKsL7BNu6Guy0v+uTlwsxYQxjspXzqLYQs=
+    - name: Inject GitHub Token into Environment
+      if: inputs.github_token != ''
+      uses: fossi-foundation/nix-eda/.github/actions/nix_daemon_inject_github_token@5.5.0
+      with:
+        github_token: ${{ inputs.github_token }}

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 8f933e5..4e07d5c 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml

@@ -8,39 +8,16 @@
   build-and-test:
     strategy:
       matrix:
-        os:
-          [
-            {
-              name: "macOS 14",
-              family: "macOS",
-              runner: "macos-14",
-              archs: "arm64",
-            },
-          ]
         pdk-family: [sky130, gf180mcu]
-    name: Build ${{ matrix.pdk-family }} with Ciel | ${{ matrix.os.name }} | ${{ matrix.os.archs }}
-    runs-on: ${{ matrix.os.runner }}
+    name: Build ${{ matrix.pdk-family }} with Ciel | (Nix/x86_64-linux)
+    runs-on: ubuntu-24.04
     steps:
-      - name: Clear Build Space
-        run: |
-          echo "== Before =="
-          df -h
-          for xcode in /Applications/Xcode*; do
-            echo "== Removing $xcode … =="
-            rm -rf $xcode
-          done
-          echo "== After =="
-          df -h
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
         with:
           fetch-depth: 0
-      - uses: DeterminateSystems/nix-installer-action@main
+      - uses: ./.github/actions/setup_nix
         with:
-          determinate: false
-          extra-conf: |
-            access-tokens = ${{ env.GITHUB_ACCESS_TOKEN_STR }}
-            extra-substituters = https://nix-cache.fossi-foundation.org
-            extra-trusted-public-keys = nix-cache.fossi-foundation.org:3+K59iFwXqKsL7BNu6Guy0v+uTlwsxYQxjspXzqLYQs=
+          github_token: ${{ secrets.GITHUB_TOKEN }}
       - name: Install Magic, Ciel, GHR
         run: |
           nix profile install github:fossi-foundation/nix-eda#{ghr,magic-vlsi} github:fossi-foundation/ciel
@@ -53,7 +30,7 @@
           echo "PDK_ROOT=$PWD/root" >> $GITHUB_ENV
       - name: Build with Ciel
         run: |
-          ciel build --include-libraries all --pdk-family ${{ matrix.pdk-family }} --use-repo-at open_pdks=$PWD --jobs $(sysctl -n hw.logicalcpu) --clear-build-artifacts $(git rev-parse HEAD)
+          ciel build --include-libraries all --pdk-family ${{ matrix.pdk-family }} --use-repo-at open_pdks=$PWD --jobs $(nproc) --clear-build-artifacts $(git rev-parse HEAD)
       - name: Push if New Tag
         if: github.ref_type == 'tag'
         run: |